Question

A container is filled to a depth of 21.0 cm with water. On top of the water floats a 27.0-cm-thick layer of oil with specific gravity 0.600. What is the absolute pressure at the bottom of the container?

Answer 1

Gravitational acceleration = g = 9.81 m/s²

Density of water = ₁ = 1000 kg/m³

Specific gravity of the oil = s = 0.6

Density of the oil = ₂

₂ = s₁

₂ = (0.6)(1000)

₂ = 600 kg/m³

Height of the water = H₁ = 21 cm = 0.21 m

Height of the oil = H₂ = 27 cm = 0.27 m

Atmospheric pressure = P_atm = 101325 Pa

Absolute pressure at the bottom of the container = P

P = P_atm + ₁gH₁ + ₂gH₂

P = 101325 + (1000)(9.81)(0.21) + (600)(9.81)(0.27)

P = 104974.32 Pa

Absolute pressure at the bottom of the container = 104974.32 Pa